Calculating machine



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CALCULATING MACHINE 13 sheets-sheet Filed Sept. 12, 1941 INVENTOR ML Tf1? E /1/47/7'/ AT1-ORN E115' 'May 4, 1943. w. E. MATHI CALCULATING MACHINE Filed Sept. l2, 1941 13 Sheets-Sheet 4 459 gal-L Rm mw N R mm Mm x A May 4, 1943. w. E. MATH, 2,318,241

CALCULATING MACHINE Filed sept. 12, 194i 13 sheets-sheet 5 FlE E INVENTOR 14440512 t". MATH/ Bv ATTORNEYS W. E. MATH! CALCULATING MACHINE 13 Sheets-Sheet 6 Filed Sept. l2, 1941 INVENTOR ATTORN EYS May 4, 1943 W. E. MATH; M8243 CLCULTING MACHINE Filed Sept, l2, 1941 13 Sheets-Sheet 7 llfllh INVENTOR ML75/P E MAT/w ATTORN EY `May 4, 943.

-ALCULA'TI NG MACHINE Filed Sept. l2, 1941 13 SheetSmSheeT. 8

V am Mdm@ o 1l l ma' M INVENTOR WALTER [/1//247/9/ BY TTRNEY5 May 4, 1943e w. E. MATHE CALCULAIING MACHINE Filed sept. 12, 194i 13 Sheets-Sheetl 9 INVENTOR ifi/ALTE@ E MAT/1f av ATTORNEYS May 4, 1943.

w. E. MATHE 2,318,24E

GALCULATING MACHINE INVENTOR 14m TU? E /WATH/ ATTORNEYS 'May 4, i943. W. E. MA1-H1 2,333,241

CALCULATNG MACHINE Filed Sep'. l2, 1941 l l5 Sheets-Shea?, l2

[il INVENTOR ML75? E.' MAT/w ATTORNEYS 4Maly 4,l 194"n w. E. MATHi CALCULATING MACHINE 13 sheets-sheet 15 Filed Sept. l2, 1941 m EN mM .N. mf 1P m.. WA

ATTORN EYS Patented May 4, 1943 CALCULATING MACHINE Walter E. Mathi, Oakland, Calif., assigner to Marchant Calculating' Machine Company, a corporation of California Application September 12, 1941, Serial No. 410,558

(Cl. 23S-62) 9 Claims.

This invention relates to calculating machines of the type capable of performing division calculations and has particular reference to mechanism for arresting operation of a calculating machine during a division calculation.

One object of the present invention is to provide improved means for stopping a calculating machine during division, selectively either permitting the completion of a division operation in a current order and the determination of the true quotient digit therein, or immediately stopping the machine.

A further object of the invention is to simplify the construction and operation of a division control mechanism of the character described.

The invention is illustrated as applied to calculating machines constructed in accordance with the disclosure of the Harold T. Avery Patent Number 2,216,659, issuedA October iirst, 1940, to which reference is hereby made for a disclosure of a complete calculating machine, including mechanisms not specifically disclosed herein. It is to be understood, however, that the invention may also be applied to other calculating machines capable of performing division calculations or the like.

The manner in which the above and other.

objects of the invention are accomplished will be readily understood on reference to the following specification when read in conjunction with the accompanying drawings wherein:

Figure 1 is a plan view of the machine in which the present invention is incorporated. t

Figure 2 is a sectional elevational view, illustrating the manually set selection mechanism, the power set selection mechanism, and a portion of the actuator mechanism.

Figure 3 is a section taken along the line 3-3 of Figure 2. illustrating thev typical construction and mounting of a key.

Figure 4 is a sectional view through the ve selection plates in one of the decimal orders.

Figure 5 is a transverse sectional view, taken through the carriage, illustrating the snail cams which are driven by the accumulator dials, and the follower means operable thereby.

Figure 6 is a sectional view illustrating the keyboard lock mechanism.

l Figure '7 is a schematic View .showing the various units and their relation to the driving means.

Figure 8 is a side elevational view of the mechanism for controlling the setting clutch.

Figure 9 is a side elevational view of the mechanism for limiting operation of the main clutch to a single cycle.

Figure 10 is a side elevational view of the mechanism for controlling operation of the main clutch.

Figure 11 is a side elevational view illustrating the mechanism for raising and lowering the dipping portion of the carriage.

Figure 12 is a side view of mechanism utilized to control movement of the dipping portion of the carriage.

Figure 13 is a side view of the mechanism for releasing the actuator pawls at the start of a machine operation.

Figure 14 is a side elevational view of the reverse unit and controls therefor.

Figure 15 is a side elevational view of the restore clutch and controls therefor.

Figure 16 is a side elevational view illustrating part of the division control mechanism and the stop key mechanism.

Figure 17 is a detail view illustrating part of the stop key mechanism.

Figure 18 is a side elevational view showing part of the division control mechanism.

Figure 19 is a detail View illustrating the means for tripping the division control lever.

Figure 20 is a side elevational View illustrating the means controlled by the division sensing mechanism.

Figure 21 is a side elevational view of the mechanism for operating the shaft which controls the enabling and disabling of the division sensing mechanism.

Figure 22 is a plan view of the division control gate and one of the division sensing levers associated therewith.

Fig. 23 is a plan view in section illustrating a portion of the division control mechanism, particularly the means for transmitting from a lower order of. the sensing and control mechanism to the next higher order, the decimal value of a value set in the lower order, and is taken substantially along the line 23-23 of Figure 24.

Figure 24 is a side elevational view illustrating the division sensing mechanism and its relation to the accumulating mechanism.

Figure 25 is a detail view of certain of the elements of Figure 24, showing them in an alternate position in which the sensing levers are effective to block the division control gate.

Figure 26 is a view similar to Figure 24 showing a sensing lever` blocked out of operative position.

Figure 27 is a plan view, illustrating two of the division sensing units.

Figure 28 is a sectional plan view of the division control mechanism, and is taken on the line 28-28 of Figure 26.

Figure 29 is a side elevational view, illustrating the relationship between the division control v visor is subtracted as many times as possible from the dividend to obtain the quotient. ,The first quotient digit is derived by subtracting the divisor as many times as possible from the highest series of denominational orders of the dividend in which the divisor is contained, the second quotient digit by subtracting the divisor from the highest remaining series of orders in which it is contained, and so on.

.This method of determining the quotient is generally carried out by setting up the dividend in a series of dials in an accumulator register mounted on a shiftable carriage, while setting up the divisor in a series of keys on a keyboard. The carriage is usually so positioned relative to the various keys depressed on the keyboard, or

vice versa, that on beginning the multiple subtraction process, the divisor will be subtracted from the highest series of 'register dial orders into which such divisor can be contained, thereby deriving the rst quotient digit which appears on a suitable counter. Thereafter, the carriage .is shifted one order to the left, which has the same effect as multiplying the remainder by ten, and the same procedure of deriving the next lower order quotient digit is followed through.

It is ofen desirable to stop the machine before the quotient digit in the last order of the counter is reached, while at the same time obtaining true quotient digits in those orders in which the division has been completed.

Again, it is often desirable to stop the machine before the end of the division operation in a cer tain carriage position, as for example, if the division operation has accidentally been initiated with a setup in the accumulator register dials and none in the keyboard. In this case, the machine will ordinarily continue to operate indefinitely because no subtraction will actually take place.

Another example of a case in which it would be desirable to rstop the machine before obtain- 'before such digit completion" is effected in the actuated order.

Manually set selection, mechanism The machine in connection with which the present invention is illustrated is of the key-set type in which means are provided for first setting one factor of the calculation upon a keyboard and subsequently effecting operation of the machine by manipulation of a separate control key or bar.

The mechanism for setting up the first factor cf a calculation, such as a dividend, may be considered as comprising a manually operated portion and a power operated portion, the manually operated portion being designed to be moved to a selected controlling position by the depression of value keys on the keyboard, and the power operated portion being designed to be brought into operation immediately before operation of the calculating mechanism and to act under control of the manually set selection mechanism to move elements of the calculating mechanism into the proper position to cause operation of such calculating mechanism to enter the values which are set up on the keyboard into the accumulator register.

The .various value selecting keys i6@ (Figures 1 and 2) of the keyboard are arranged in a series o banks, each bank including progressively arranged keys ranging from zero to nine in value, and, as disclosed in detail in the above Avery Patent Number 2,216,659, each key itil is slidable vertically in a channel frame lili (Figure 3). Compression springs 462 are provided to normally maintain the keys i in their illustrated raised positions.

All of the key stems H33 oi the value i keys are of the same length and each has a cam ing the true quotient digit in a given carriage position would be a case in which the division operation was initiated with the carriage posi tioned too far to the left, as for example, if the accumulator register and keyboard relation were such that a single digit would have to be subtracted a large number of times from a three or four or larger order number before obtaining the rst quotient digit.

The present invention provides a single depressible key which, when depressed part Way through its full stroketo a position wherein it encounters a yieldable limit stop, will cause the machine to stop when a true quotient digit has been obtained in the actuated order of the counter, and which, when depressed to the limit of its full stroke against the urge of its yieldable limit stop, will arrest the machine immediately, and possibly extrusion' i i6 which, upon depression of the associated key, pushes to the right, as viewed in Figure 2, a slotted key locking slide il?, slidably supported on the under side of the channel frame i@ i, thereby releasing any other latched down key in the same section. Upon full depression of any value key, the slide lil is returned to its initial location under the urge of a spring llt, and by overlapping the upper end of the extrusion i i@ ein the depressedkey stem, latches the depressed Disposed beneath the value keys itil in each bank is a differentially settable bar l2@ which is pivotally suspended from the associated channel frame lill by means of two parallel links i223 and 029. This bar l2@ has nine identical divergent notches i3@ therein, each of which terminates in a rectangular slot liti proportioned to receive the end of the associated key stem it so that the bar i2@ will lbe accurately positioned. The key stems E63 are spaced equal distances apart, and these distances are slightly greater than the spacing between the successive slots 36 so that each succeeding slot i3l will be spaced one increment further away from the cooperating key stem. Thus depression of a value key will cam the bar l2@ to the right a number of increments equal to the value represented by the depressed key.

Such movement of the bars i2@ is utilized to set up a mechanical representation of the selected value to control the actuating mechanism accordingly, and for this purpose segment members E32 are connected by means of pin and slot connections |63 to respective ones of the bars i2@ and are pivotally mounted on a rod i3? extending across the machine. Each of the segment members l32 is provided at opposite ends thereof with arcuate racks |88 and I 8l which serve to transmit the movement of the associated diiierential bar |29, respectively, to a pinion I4I of a check dial assembly I 48 rotatably mounted on a rod I4| and to a gear I8| oi' a cam unit |46 which is rotatably mounted on a rod Ill and which is positioned by such movement to form a mechanical representation of the value set up on the respective key bank.

Each cam unit |48 comprises a gear |5| and ilve cams integrally connected thereto, one of which is shown at |52. Each of the cams has two high points |68 and two low points |6I on its periphery. The cams are so staggered that no high or low point on one cam is aligned with a high or low point on another cam.

As is described in detail in the above mentioned Avery patent, the various cams on each cam unit' |48 are so arranged that upon depression of an associated value key |00, the gear I of the same order will be driven by the arcuate rack |39 to rotate the cam unit |46 to a position wherein one of the high points of one only of the cams will be positioned in the path of a nose 2| I oi one of a set of five feeler arms 2|I) on one side of the cam unit |46, or in the path of a nose 2|9 of one of a set of ve feeler arms 2| 1 on the opposite side of the cam unit |46.

Power set selection mechanism Upon depression of one of the calculation control keys, such as a division key 910 (Figures 1, 16, and 18) or an add key 800 (Figure l), a setting clutch 430 Flgures 7 and 8) is engaged to rotate one-half revolution, as will be more fully described hereinafter, to likewise rotate a setting shaft 43|. Keyed on the setting shaft 43| are a i number of pairs of complementary cams identical 4to cams 228 and 22| (Figure 2). and each nair has an associated cam follower 224 pivoted on a cross rod 225 and provided with a roller 222 in engagement with the cam 220 and a second roller 223 in engagement with the cam 22|. As the shaft 43| rotates in a counter-clockwise direction, the cam followers 224 are rocked and, through links 226, impart a counter-clockwise rocking,r movement to a series of levers 2|4 pivoted on a shaft 2|5 extending across the machine.

A shaft 2I3, supported by the levers 2'4, has pivotally mounted thereon the groups of feeler arms 2|0, hereinbefore described, one of these groups being located ,adjacent each of the cam units |48. During the leftward movement of the levers 2|4, and consequently of the shaft 2I3, the feeler arms 2|0 are moved by the shaft 2|3 until each of the noses 2|| engages the periphery of the respective cam in the cam unit |46, thereby causing each feeler arm 2|0 to pivot about the point of contact between its respective nose and the periphery of its associated cam. The balance of the forward movement of the shaft 2I3 b': the cam followers 224 effects forward mrvrmen': of the lower ends of the feeler arms 2|G. and t'fis movement is transmitted through links 2lb to feeler arms 2|1 aligned with the associated feeler arms 2|0. The arms 2|1 are then rocked 'n a clockwise direction about a fixed shaft 2 il until their noses 2|9 engage the periphciies of 'sie respective cams at points substantially diametrically opposite that engaged by the noses 2|| of the associated feeler arms 2li).

To accurately position each cam unit |48 during the power sensing operation, a pawl 238 (Fr:- ure 2) in each order is mounted on the shaft 2 |8 and is urged by a spring 23| against a pin 232 on one o! the links 2|4. During the portion oi' the setting clutch operation in which the levers 2|4 are rocked counter-clockwise, the pin 232 releases the pawl 230 enabling the same to be engaged between adjacent teeth on thegear |5| by its spring 28| and thereby holds the cam unit |46 from displacement during the power sensing operation.

As was mentioned hereinbefore, each of the cam units |46 is so arranged that only one of the associated pairs of feeler arms 2|8 and 2|1 of any group will have their respective noses in engagement with the high or low point of a cam at any one value setting of the respective key section. Thus, one of the feeler arms 2|8 will be rocked a considerable angle about its supporting shaft 23 to one side or the other of a medial position. depending upon whether its nose 2I| is in engagement with a high point |68 or a low point IGI of its respective cam. All of the other feeler arms will, since their noses are held in engagement with the concentric peripheral portions of their cams, be held in medial positions with their upper ends located substantialiy in the position illustrated in Figure 2.

Each of the feeler arms 2|!) is connected through a pin and slot connection 206 with one of a series of flve plates |12 pivotally suspended from a sleeve |69 (Figures 2 and 4) which is rotatable on a stationary rod |10, there being one of such series of -plates for each order of the machine. Pivotally mounted on each plate |12 is a set of entrained gears |13 and |14, the latter meshing with a laminated gear |89 keyed to the sleeve |69.

Actuator mechanism From the above it will be seen, that depending on the selection made, four of each group of five ofthe selection plates |12 will be held in medial positions similar to that indicated in Figure 2, while the fifth will be moved forward or rearward until the lowermost gear |13 thereon meshes with an aligned gear, indicated at |15, on an actuator shaft |68, orwith an aligned gear, indicated at |16, on an actuator shaft |61 (see also Figure 7).

Gear |15 is one of the group |11 of four gears keyed on the actuator shaft |66 and adapted to mesh with the lowermost gears |13 on the four leftmost selection plates I 12 in each order. Likewise, gear |16 forms one of a group |18 of five gears mounted on the shaft |61 and adapted to mesh with the gears |13 on the five selection plates. The three leftmost gears of this latter group are keyed to the shaft |61 while the two rightmost gears |88 and |99 are free on the shaft |81 and mesh with gears |95 and 280, respectively, keyed on a third actuator shaft |68.

The shafts |66, |61, and |68 are connected to a cyclically operable main clutch 428 (Figures 7, 10, and 15) ln a manner to be described presently, so that the shaft |66 rotates through 180 for eac-h cycle (one-half revolution) of operation of the clutch 428, and the shaft |61 rotates through for each cycle, while the shaft |68 rotates through 30 for each cycle of the main clutch. The diameters of the various gears in the two gear groups |11 and |18 are. so arranged that for each mainr clutch cycle, the laminated gear |89 (Figures 2 and 4) will be rotated by one of the gears of the groups |11 and |18, a number of increments corresponding to the value of the associatf key |00, if such has been depressed. If no key has been depressed, the selection plates |12 will be so arranged that none of the gears in either of the groups |11 and |18 will become operative to drive the selection plate gears |13.

Means are provided for locking the selection plates |12 in any of their three operative positions throughout a machine performance and comprises a locking bail 236 (Figure 2) extending across the machine and pivotally supported on a rod 231, the bail being adapted to be moved into engagement with one of three notches 238 formed on each of the selection plates |12, after a selection has been made. The bail 236 is connected through link 528 to a cam follower 529 pivoted on the rod 225 and having rollers 53!) and 53| thereon -in engagement with complementary cams 526 and 521, respectively, keyed on the setting shaft 43E so that operation of the setting clutch will effect locking of the selection plates |12 after the feeler Varms 2|@ and 2|1 have been rocked to effect a power selection.

'Accumulator' mechanism From the foregoing description of the selection and actuator mechanisms, it is apparent that a number comprising a plurality of gures can be registered upon the various sleeves |62 (Figure 2) by differentially driving the gears |89 attached thereto various proportionate distances. However, in order to perform any mathematical computation mechanism must be provided for advancing a superior registering element one extra increment whenever the next lower registering element has completed registration of ten digits in a machine operating according to the decimal system.

In the present machinethis function is accomplished by accumulator mechanism having indicia bearing dials 219 (Figure 2) visible through sight openings 3|@ (Figure 1) and carried in a carriage25ll. The carriage is supported for endwise movement by shafts 252 and 2t@ (Figure which slide through bearings (not shown) supported by the stationary portion of the machine.

Carriage shifting mechanism (not shown) of the type disclosed in detail in the above Avery Patent 2,216,659 is preferably provided-to shift the carriage step by'step into any of a plurality of different positions.

The accumulator mechanism employed in the present machine is also disclosed in detail in the above Avery Patent 2,216,659 and, therefore, it is believed that a brief description of the same and the driving connections thereof will be sufcient for an understanding oi' the present invention.

The accumulator mechanism comprises in part, a Shaft 262 supported by spaced carriage brace plates 255, which shaft serves as a pivotal support for a plurality of plates E, ordinarily spaced from each other, and all connected to a common bail 229. The bail 26@ is known as a dipping bail by means of which the entire body of plates 22S can be simultaneously rocked about the shaft 262 during performance of a calculation such as division.

The various denominational registering units of the accumulator mechanism are supported by the rockable plates 26S, each unit forming an assembly between two of these plates. Each .unit comprises a dial 219.(Figure 2) connected by differential planetary mechanism (not shown) to both a corresponding gear 213 and to the next lower order dial 219 whereby both digitation and tens carry can be effected concurrently. The

gear 213 is rotatably mounted on a rod 210 (Figure 11) supported by the plates 268 and meshes General calculations drive Power for effecting operation of the variousv mechanisms of the machine, including the setting clutch d3!! and the main clutch 428, is derived from a motor 640 (Figure 7) the armature shaft of which is connected through a coupling 642 and a suitable safety slip clutch 644 to a pinion 525 entrained with a gear train including gears 666, ttl, 362, 650, and M5, the latter being mounted on the driven side of the main clutch l42B. When the main clutch is engaged, power is transmitted thereby through a reverse unit generally indicated at 552 (to be described hereinafter) to the above mentioned actuator shafts |66 and itl through a gear train including gears Q52, 3813, 525, 286, and lll. 'I'he shaft |68 is driven by the shaft ll through gears #38S and (it.

The setting clutch d3@ has a gear @32' mounted on the driven side thereof which meshes with a gear 6ft suitably coupled to the motor driven gear 362. The gear 362 also drives a gear'tl fastened on a rotatable shaft tilt on which is also `mounted a restore clutch 10@ to be described hereinafter.

Setting clutch The present machine employs a cyclically operable setting clutch and mechanism operable thereby to effect various operations incident to the commencement of a calculation under the power of the motor. The details of this clutch are disclosed in the aforesaid Avery Patent Number 2,216,659.

Operation of the setting clutch 23@ (Figures '1 and 8) is under the control of the machine operator, particularly through the instrumentality of various operation control keys. rhe control of the clutch d3@ is such that, immediately upon de.- pression of one of the operation control keys, a clutch dog 396 is rocked away from the clutch to enable engagement of the clutch and to start the motor so as to drive the setting shaft (53E. Normally, however, the clutch clog 396, which is keyed on a rockable shaft 529 is held in engagement with the clutch by a spring 522 tensioned between the clutch dog and -a frame stud, and when in such position, holds the setting clutch out of engagement.

To permit operation of the setting clutch by the control mechanism hereinafter described, an operating bar 523 is provided which is supported by a parallel link arrangement comprising levers dil@ and 525 pivotally supported at Sd and 5F31, respectively, and connected to the bar 523 at 522 and Ei, respectively. The bar 523 is normally held in its illustrated raised position by a tension spring 5i@ extending between the lower end of the lever 522 and a frame'stud (not shown).

To enable lowering of the bar 523 to rock the clutch dog 3% out of engagement with the setting clutch 232, a bell crank bf2 is pivoted to the lever 505 at 5|@ and is provided with a notched arm 5M, the notch of which embraces a lateral extension |5 on the dog 394. When the bell crank is in the position in which it is normally held by a spring 5| 5, tensioned between the other end of the bell crank and the control bar 503, it is capable of rocking the clutch dog 394 upon depression of the bar 503. Means (not shown) are, however, provided to rock the bell crank 5|2 from engagement with the dog 394 during the first setting clutch cycle, to limit operation of clutch 430 to a single cycle (one-half revolution) since this is all that is required to operate all of the mechanism to be actuated by the clutch in conditioning the machine for operation.

In addition to operating the power set selection and locking mechanism, as previously described, the setting clutch causes dipping of the accumulator mechanism to mesh the gears 21| (Figures 2 and 11) with the laminated actuating gears |89, initiation of operation of the main clutch, and

conditioning of the reverse. unit control mechanism for operation, as will appear hereinafter.

Dipping of accumulator plished by lowering the 'bail 269 and supporting plates 266 about the pivot rod 262.

The means for dipping the bail 269 at the start of a calculation and for thereafter elevating the same to its illustrated raised position at the completion of a calculation comprises two vertically slidable links, one of which is shown at 566 (Figure 11), guide over pins 561 and provided with rollers 568 engaging the top and bottom surfaces of one leg of the bail 269. The links 566 are urged upwardly by springs 569 tensioned between the links and frame studs. The links are pivoted to cam followers 510 at 512, which cam followers carry-rollers 513 held in engagement with cams 514 keyed on the setting shaft 43| so that the links 566 are positively pulled down upon operation of the setting clutch.

Means are provided for latching the accumulator mechanism and links 566 in their lowermost positions throughout a calculation performance This means includes latch levers 515 in the form of bell cranks pivoted at 516 and each having a nose 511 formed at the upper end thereof to engage ear 518 on the respective cam follower 510. The latch levers 515 are urged counterclockwise into engagement with the ears 518 by springs 519 tensioned between the levers 515 and frame studs so that when the links 566 are dipped, the ears 518 ride past the noses 511 andare latched therebeneath, thus holding the links depressed until the latch levers A515 are released as will appear presently.

Pawls (Figures 2 and 11), which are normally held in pawling relation with the gears |89 when the machine is not operating, are released in time with the dipping of the accumulator so that release of the gears |89 is properly coordinated with the meshing of 'gears 21| therewith. 'I'he pawls 20| are loosely keyed to a shaft 202 to which are fixed arms 586 (Figure 13), connected by pin and slot connections 581 to levers 588 pivoted c-n the rod 225 and provided with rollers 589 adapted to be engaged by certain of the cams 514. When the setting shaft 43| ro,

tates, the cams 514 rock the levers 558 and `the pawls 20| in those orders in which a value is to lil be entered are thusA released. A detent mechanism, such as the conventional one illustrated in Figure 13, is provided, which comprises a lever 532 pivoted on a shaft 533 and urged clockwise by a spring 534. such movement thereof being limited by a stop (not shown). The lever 532 cooperates with a nose 53.5 formed on the lever 588 to retain it in either of the positions in which it is capable of being set, so that the pawls 20| will not reengage the gears |89 until the restore clutch operates as will be described hereinafter.

Means are providedfor releasing the dipping carriage latch levers 515 at the conclusion of a calculation so as to enable the accumulator to be again raised to its upper illustrated position by the springs 569 to permit shifting of the carriage, clearance of the accumulator, et cetera. These include levers 580 vanci 584 (Figure 12) secured to a rockable shaft 58|, the latter lever engaging an ear 592 on a lever 59| pivoted at 590. The lever 59| has an extension thereon lying in the path of rotation of a roller 593 eccentrically mounted on a disc A which is driven by the restore clutch 100 (Figures 7, ll, 15, and 16) when the same is engaged as an incident to completion of a calculation, as will be described hereinafter.

Upon rotation of the disc 100A in a counterclockwise direction the roller 593 rocks the lever 59| clockwise, thereby rocking levers 580 and 584. Lever 580 abuts a roller 536-on a lever 539 (Figure 11) having an extension 583 underlying one of the latch levers 515. The lever 539 is also suitably connected to another similar lever having a like extension underlying the other of the latch levers 515 so that when the shaft 58| is rocked by lever 584 the latch levers are concurrently released from restraining engagement with the cam followers 510.

As a further incident to the rocking movement of the shaft 58| during release of the latch levers 515, the roller 536 engages a cam surface 531 (Figure 13) on the lower edge of the rocking lever 588 thereby rocking this lever to cause reengagement of the pawls 20| with the gears |89.

Also rotatable by the restore clutch 100 is a cam 596 (Figure l1) which is employed to prevent the link 566 from rising too rapidly under the action of springs 569 when the cam followers 510 are released-by the latch levers 515.' A lever 591 fixed to a rockable shaft 600 engages the cam 596 While levers 599 also fixed to the shaft 600 are joined by pin and slot connections 602 to the links 566 so that the rate of rise of the links 566 will be governed by rotation of the cam 596.

Main clutch operation The main clutch 428 (Figures '1, 10, `and 15) is engaged and its operation initiated by the setting clutch. Thus, when any one of the operation control keys is depressed, and the setting clutch is started in operation, as has been previously described, the main clutch is automatically engaged to drive the actuator mechanism and may be held engaged for one or more cycles of operation, depending upon the type of calculation being performed.

'Ihe main clutch structure has been described in detail in the above mentioned Avery Patent 2,216,659 and is similar to that of the setting clutch, being mounted on a shaft 429 (Figure 10) and controlled by a clutch dog 395 pivotally mounted on a. shaft 6|| and urged into engagement with the main clutch by a spring 6|2 tenage 6|0 connected'to the left end of the dog.

The arrangement is such that when the clutch A- dog 395 is held in engagement with the clutch as illustrated, the clutch is disengaged. How-y ever, when the dog 395 is rocked'clockwise from its seated position, the main clutch becomes engaged to drive the actuator mechanism.

The means for causing engagement of the main clutch comprises a lever 146 (Figure 10) /fulcrumed on the shaft 50| andv provided with a roller 145 spring pressed into engagement with va cam 141 keyed on the setting clutch shaft 43|. A member 603 is pivoted on the lever 146 at 604 and is urged clockwise with respect to the lever 146 by a spring 6|3 tensioned between an ear on the lever 146 and an ear 6|4 on the member 603, the latter forming a limit stop which engages the lower edge of the lever 146. The member 603 is provided with a nose SI adapted to engage a notch 6|6 in the main clutch dog 395. Therefore, as the cam 141 is rotated during the setting clutch cycle, the member 603 engages and rocks the main clutch dog 395 out of engagement with the main clutch 428 while continued rotation of the cam 141 enables the rocking lever 146 to return to the position shown in Figure 10, so as to permit the clutch dog 395 to contact with and stop the clutch when it is free to do so.

To provide for continuous multicyclic operation of the main clutch, as occurs during division calculations, a latch 632 is provided, being pinned to a rockable shaft 625 and urged clockwise by a spring 633 tensioned between the latch and a frame stud. A roller 635 is mounted at the upper end of the latch 632 in a position to be latched under a lateral projection 620 on the tail of the main clutch dog 395. When the clutch dog 395 is rockedclockwise from the position illustrated in Figure l0 and the latch 632 is permitted to be rocked by the spring 639, the roller 634 will engage the under surface of the extension 620 on the clutch dog, permitting multicyclic operation of the main clutch.

M ain reverse unit Means are provided for reversing the direction of drive of the actuator mechanism by the main clutch, and this means comprises the hereinbefore mentioned reverse unit 455 (Figures 7 and 14), the construction of which is described in detail in the above mentioned Avery Patent The setting of the reverse unit is controlled by the various calculation control mechanisms, such as the division control mechanism, but it is actually set by cam means actuated by the setting clutch.

A pendular lever 545, forming a control member for the reverse unit, is pinned on a rockable shaft 545 and is pivotally connected to a bar 541 which is supported intermediate its end by a link 508 having a bifurcated end thereof guided over a sleeve tted on the setting clutch dog shaft 50|. A spring 560 tensioned between the link 553 and a frame stud normally holds the bar 541 to the right in its illustrated "positive drive position with an upturned end 549 thereon located directly under a lug 555 on a reverse control member 469 pivoted on a shaft 386.

Upon operation of the setting clutch, with the bar 541 inits rightmost illustrated position, the bar is rocked upward to set the reverse unit in its illustrated position. This is accomplished by plate 552, first clockwise, at which time an ear 553 on the plate and underlying the bar 541, raises the bar to engagethe upturned end 549 with the lug 555 and thus rocks the reverse control lever 469 to the position illustrated in Figure 14 if it is not already in that position. When so set, the control lever 469 controls the reverse unit to drive the actuator mechanism in its positive direction.

However, when the pendular lever 545 is rocked clockwise from its illustrated position against the urge of spring 560 the upturned end 549 of the bar 541 will be 'positioned under the lug 554 of the reverse control member 469 and, therefore,

during ,the succeeding setting clutch cycle, the

member 469 will be rocked clockwise from the position shown in Figure 7 to set the reverse unit to drive the actuator mechanism in a subtractive direction. Restore clutch ously described; to control the rate of return ofV the accumulator from its dipped position; and to perform certain functions hereinafter described in connection with division operations. This clutch is controlled jointly by the dipping of the accumulator and by the operation of the main clutch dog 395 in such a way that whenever the accumulator is in its lower position and the main clutch dog 395 is seated home in a notch in the main clutch, the restore clutch will be engaged.

The restore clutch is of the cyclically operable type similar to that disclosed in the patent to Friden Number 1,643,710, issued September twenty-seventh, 1927, and a clutch release dog 1365 is provided to normally hold the clutch dis'- engaged.

The lowering of the accumulator, by rocking the shaft 600 (Figures lland 15) counter-clockwise, creates .a spring bias tending to move the clutch release dog 905 away from the restore clutch to permit engagement thereof, but as this dog is normallylatched by a member 16E, the spring is prevented from becoming effective until completion of the main clutch operation. Raising of the accumulator, as described hereinbefore, is initiated and controlled by the restore clutch, and this movement is utilized to reverse the spring bias on the restore clutch release dog so as to tend to return it home so that, as the restore clutch cycle is finished, the clutch release dog is spring pressed into the full cycle notch formed in the clutch housing, bringing the restore clutch to rest at the completion of one cycle of operation thereof.

The restore clutch is mounted upon and driven by a shaft 649 (Figures 7 and l5) having a gear 36| xed thereto and meshing with the power driven gear 362.

The clutch release dog 405 is in the form of a bell crank freely supported on the shaft 600 and has a nose 102 thereon adapted to engage in a notch formed in the housing of the restore clutch 100 to effect disengagement of the clutch. For

controlling the clutch release dog 405 an M- 105 compressed between itself and the left arm o! the clutch dog 405.

An arm 122, keyed on the shaft 600, and thus rocked by dipping movement of the accumulator, is reslliently connected to the M-shaped member 103 by a link unit generally indicated at 123. 'Ihis unit comprises a pairv of links 115 and 116 lying side by side, the former being plvoted on a pin 109 on the arm 122, and having an elongated slot on the opposite end thereof embracing a pin'112 on the member 103, while the link 116 is plvoted on the pin 112 and has an elongated slot embracing the pin 109. Each link has a cut out portion into which two tenons extend formlng a retainer for a compression spring 114 which embraces the tenons of both links. Thus, the spring 114 will tend to retain the link unit extended in the position illustrated in Figure and will be compressed if the unit is lengthened or shortened.

As the setting clutch rotates, the main clutch dog 395 is withdrawn from contact with the main clutch and an extension 408 on the dog is withdrawn from beneath an-ear 110 of the latch 10| which is pivoted on a frame plate, thus permitting the latch to be rocked counter-clockwise by a spring 111 tensioned between the latch and a frame stud. An ear '118 on the latch is thus brought into engagement with a notch 119 formed on thev member 103 to prevent counter-clockwise movement thereof until the main clutch has been disengaged by reseating of its dog 395 in one of the full cycle notches of the main clutch 428.

The lowering of the accumulator, however,

tends to engage the restore clutch even before the A main clutch engages, and a second restraining means is provided to prevent such operation. The left foot of mem'ber 103 is provided with a shelf 120 overlying one end of a bell crank 121 which is rockably supported on the shaft 611.

The other end of the bell crank 121 is provided with a roller 101 engaging the periphery of a cam 103 keyed on the setting shaft 431. On rotation of the setting clutch, therefore, the bell crank 121 is rocked and the shelf 120 is raised by the end of the bell crank to rock the M-shaped member 103 slightly clockwise about the shaftl 600. This raising of the member 103 not only insures that the lug 118 of the latch 101 will properly engage in the notch 119 when the main clutch is engaged, but also provides for the situation occurring in certain division operations, when operation of the setting clutch does not cause engagement of the main clutch. In this situation, the latch member 10i is not permitted to rock and the cam 108 serves to delay operation of the restore clutch until near the end of the setting clutch cycle, the reason for which will appear in a description of the division mechanism herein'- after.

As the setting clutch continues to rotate, the accumulator is lowered and the shaft 600 is rocked counter-clockwise by the arm 599 (see also Figure 11) keyed thereto. Arm 122, also keyed to the shaft 600 is thus lowered, and since the M-shaped member 103 is held by the latch member 101, the link unit 123 is lengthened and spring 114 is compressed.

The parts remain so positioned until the main clutch dog 395 is permitted to reseat in the notches of the main clutch, whereupon the extension 400 thereofstrikes the ear 110 on the latch member 101, rocking it clockwise and re moving its lug 118 from the notch 119 of the member 103. The spring 114 is then permitted to expand, shortening the link unit 123 and rocking the member 103 counter-clockwise to carry the left leg thereof, as viewed in Figure 15, down against the leftwardly extending arm ofthe bell crank 405 to move the nose 102 away from the restore clutch and cause engagement thereof.

Operation of the restore clutch, thus initiated, enables the accumulator to rise, as previously described, rocking arm 122 clockwise by virtue of its connection therewith. This movement of the arm 122 is transmitted directly to the link unit 123 to rock the member 103 clockwise and to compress the spring until the nose 102 of the restore clutch dog 405 reenters the aperture of the housing to disengage the clutch, whereby the restore control mechanism is brought to rest in the position shown in Figure 15.

Division The machine of the present invention includes means for automatically performing problems in division. In such operations, the dividend is set up in the accumulator in the usual Well known manner, the divisor is set up on the keyboard, and the automatic division key is depressed. The machine thereupon carries out automatically the operation of dividing the divisor into the dividend and registering the quotient in a counter 1800 (Figure l) carried by the carriage 250. Mechanism is provided for automatically comparing the dividend and divisor and for utilizing the indication of the relative magnitude thus obtained to select the proper ensuing operation, such as automatically shifting the carriage one step to the left, when the effective dividend is reduced to a value below that of the divisor.

Keyboard controlled mechanism The mechanism for forming a mechanical representation of a divisor value set in the keyboard comprises sensing levers 900 (Figures 24, 25, 2'6, and 27) carrying sensing shelves 901 and pivotally supported at 902 on carrier members 903 which are adjutsable so as to permit the pivots 902 to be raised and lowered for thepurpose of differentially positioning the pivots in accordance with values set on the keyboard.

The pivots 902 of levers 900 are adapted to be proportionally positioned under control of the manually set selection mechanism of a plurality of keyboard orders. Except in the orders which are Iblocked out of operation as hereinafter clescribed, each pivot 902 is positioned so as to form a mechanical representation of the value set up in its related order plus one-tenth of the value set up in the next order to the right thereof. It is unnecessary to transmit partial increments to each pivot 902 from keyboard orders Abelow the next adjacent order, and no provision for it is therefore disclosed.

Each sensing lever 900, being pivotally supported by a pin 902 on its above mentioned respective carrier member 903, is urged to rock counter-clockwise by a torsion Spring 901i tensioned between the member 903 and the sensing lever 900. The lever 900 includes a stop lug 905 (see Figure 22) which overlies and engages the member 903 (Figure 25) to limit the movement of the lever 900, and a blocking tail 906 is also provided which may be positioned to permit a division control bail 901 to rock in a clockwise direction and prevent further actuation, or to block the bail 901 from rocking and thereby cause the machine operation to continue, as will 'presently appear. 

